It can be as simple as what is in your pocket that can improve your respect as a crew member from a skipper or owner, I carry these items irrespective of the sailing I’m doing, skippering G-whizz when racing or cruising, cruising or social racing on a friends boat, crewing on a serious race boat or even when I’m on board a boat for maintenance:
A roll of electrical tape, I always have a roll in my pocket. You really won’t know its uses until you carry one. From sticking a course sheet onto the cockpit bulk head to temporarily retaining a control line out of the way when it is not in use, making a “Fish hook” (a broken strand in a wire rope) safe by wrapping it or just temporarily attaching one object to another. A benefit the tape provides is a midly secure holding while releasing (breaking) with a bit of tension.
A bosun’s knife will be your best friend, it has a sharp knife the uses of which are obvious (Keep it sharp though), a marlin spike which will come in very handy for getting those knots undone that have been secured for some time or those knots that someone else tied earlier in the day, there are lots of other uses that will make themselves obvious when you have this item in your pocket, some bosun knives also come with a shackle key which is a bonus. One little tip put a wrist strap on it if you want to keep it from Davy Jone’s locker.
About a meter or two of 2 to 3mm sturdy cord just because something will need lashing down sometime, just be prepared to donate this item to the boat, not a biggy as 100 meters of this stuff is a little more that the price of the coffee you had at the fancy cafe before you left he dock. a tip here is to put it into an appropriately sized zip top bag and it will stay contained in your pocket.
I also carry a spectra loop of about 15cm in diameter, I first carried this item to brag to some fellow crew members about my splicing skills, it sort of stayed with the other stuff I carry until I was on a delivery where we suffered a severe override on a winch, I pulled the loop out and made a prusik around the subject line and attached a second line between the prusik and another winch to take the load off the override, I will never forget the comment from another crew member “You’re a bloody magician pulling that out of the hat”. That loop has been in my pocket ever since and gets a bt of use from time time, be creative with its uses as they are almost endless. Also keep it in a plastic bag.
While not in your pocket but on your belt a decent multi tool, Leatherman is almost the generic name of these things, but any good quality one will do. Years ago I removed a 6 stack CD player (for those that can remember) disassembled it removed a stuck CD reassembled it and refitted and yes it did operate, on a charter boat using nothing more than a generic multi tool. Not a necessity, but if you have one why not wear it!
G-whizz Elan 340